As an element analyzer, a plasma generator in which air bubbles are generated in a channel that includes a narrow portion, plasma is generated in the air bubbles, and the resulting light emission in the narrow portion is measured (Patent Literature 1). However, in this device, there is a problem because the reproducibility of the plasma light emission is low.
In order to avoid the retention of the air bubbles that results in a reduction in reproducibility, a method in which a solution is moved in the channel to remove the air bubbles is disclosed (Patent Literature 2). However, in order to move the solution, there are problems in that a discharge unit such as a syringe pump is required, with the result that the size of the plasma generator is increased.
As a method for improving the reproducibility, a method in which a region other than a narrow portion is used as a portion in which the plasma light emission is measured, and the second or subsequent plasma light emissions are measured among multiple times of plasma generation in one voltage application is proposed (Patent Literature 3). However, even by such method, sufficient reproducibility is not obtained.